ITHICA, NY – A Cornell University-led research team has developed a way to generate green hydrogen through solar-powered electrolysis of seawater. As an added bonus, it also produces potable water.
A small hybrid solar distillation-water electrolysis device is key to the process, helping to produce 200 milliliters of hydrogen per hour with 12.6% energy efficiency, according to Interesting Engineering.
The prototype measures just 4 inches per side, and if scaled up, the team estimates it could reduce the cost of green hydrogen to just $1 per kilogram in 15 years. At the same time, this boon to next-gen fuel production could also help address the growing freshwater crisis.
“Water and energy are both critically needed for our everyday life, but typically, if you want to produce more energy, you have to consume more water,” said Lenan Zhang, an assistant professor who led the project.
“On the other hand,” Zhang added, “we need drinking water, because two-thirds of the global population are facing water scarcity. So there is a bottleneck in green hydrogen production, and that is reflected in the cost.”
The team saw the wasted heat from solar cells as an opportunity instead of a drawback. They could use that heat to help warm seawater until it evaporates without affecting electricity generation, utilizing the full potential of the sun’s energy.
Creating green hydrogen without squandering precious freshwater resources — which are key to making a high-purity, sustainable end product — has also been a stumbling block for the industry.
Around two-thirds of Earth is covered in water, but the oceans hold about 96.5% of that. Unfortunately, the salt content makes it unsuitable for humans to drink unless processed through desalination.
“This is a highly integrated technology. The design was challenging because there’s a lot of complex coupling: desalination coupled with electrolysis, electrolysis coupled with the solar panel, and the solar panel coupled with desalination through solar, electrical, chemical and thermal energy conversion and transport,” Zhang explained. “Now, for the first time, we can produce a sufficient amount of water that can satisfy the demand for hydrogen production. And also we have some additional water for drinking. Two birds, one stone.”
There’s even more potential for the device as a way to help cool down photovoltaic panels, which could help improve their efficiency and extend their lifespan, according to Zhang.
